Electronic Properties and Orientation-Dependent Performance of InAs Nanowire Transistors

The electronic properties, namely, the band structures, the band gaps, and the electron effective masses of hydrogen-passivated InAs nanowires grown in 〈100〉 , 〈110〉, and 〈111〉 crystallographic directions are studied using sp³d⁵s* orbital-basis tight-binding model. We then parameterize the band gaps and electron effective masses to facilitate device simulation and to study the orientation-dependent performance of n-channel InAs nanowire transistors using a top-of-the-barrier model. The 〈111〉 and 〈110〉 wire transistors have better performance metrics. The quantum-confinement effect is largest in the 〈100〉 wire, which results in a higher band gap and a heavier effective mass for relatively smaller diameter wires. The consequence is lower current, higher density of states, higher quantum capacitance, and longer delay in the 〈100〉 wire transistors. The 〈110〉 and 〈111〉 wires have a very similar quantum-confinement effect, even for the smaller diameters, which results in similar band gaps, similar effective masses, and similar performance metrics.